How Much Does a Steel Beam Cost? A UK Guide

One of the first questions on any extension or wall removal is what the steel will cost. The honest answer is it depends — but you can understand the drivers and budget sensibly.

What actually drives the price

• Beam size and length. A bigger span or a heavier load needs a deeper, heavier section, and steel is priced by weight — so a beam over a wide opening costs more than one over a doorway.
• Number of beams. A simple wall removal might need one beam; a two-storey extension or a corner opening can need several, plus posts and a goalpost frame.
• Connections and fittings. Cleats, base plates, bolts and drilled connections all add fabrication time.
• Finish. Primed is standard; hot-dip galvanising costs more but lasts far longer outdoors.
• Delivery and installation. Getting a heavy beam to site and lifting it into place is a real cost, especially on tight or upper-floor jobs.

What else to budget for

The fabricated steel is often a small part of the overall job. Also budget for:

• Structural engineer's calculations
• Building regulations fees
• Builder's labour to prop, install and make good
• Padstones, and any temporary support (Acrow props / strongboys)

How to get an accurate figure

The only way to price steel accurately is from the structural engineer's drawing, which specifies the exact sections and connections. Ballpark figures online are unreliable because they ignore span, load and fittings.

If you have an engineer's drawing, send it over and we'll give you a firm quote for the fabricated steel — see our steel beams for extensions page for how we work with self-builders.

Frequently asked questions

Is the beam the biggest cost in removing a wall? Usually not. The engineer's fees, building work, making good and installation often add up to more than the steel itself.

Does galvanising cost much more? It adds to the price but is worth it where the steel is exposed to weather or damp, because it removes decades of maintenance.

Can you quote from a photo? No — we quote from the engineer's calculations, which give the exact sizes and connections needed to price it properly.